title: Detection of serological biomarkers by proximity extension assay for detection of colorectal neoplasias in symptomatic individuals.
abstract: BACKGROUND
  Although the potential of biomarkers to aid in early detection of colorectal cancer (CRC) is recognized and numerous biomarker candidates have been reported in the literature, to date only few molecular markers have been approved for daily clinical use.
  
  
  METHODS
  In order to improve the translation of biomarkers from the bench to clinical practice we initiated a biomarker study focusing on a novel technique, the proximity extension assay, with multiplexing capability and the possible additive effect obtained from biomarker panels. We performed a screening of 74 different biomarkers in plasma derived from a case-control sample set consisting of symptomatic individuals representing CRC patients, patients with adenoma, patients with non-neoplastic large bowel diseases and healthy individuals.
  
  
  RESULTS
  After statistical evaluation we found 12 significant indicators of CRC and the receiver operating characteristic (ROC) curve of Carcinoembryonic antigen (CEA), Transferrin Receptor-1 (TFRC), Macrophage migration inhibitory factor (MIF), Osteopontin (OPN/SPP1) and cancer antigen 242 (CA242) showed additive effect. This biomarker panel identified CRC patients with a sensitivity of 56% at 90% specificity and thus the performance is sufficiently high to further investigate this combination of five proteins as serological biomarkers for detection of CRC. Furthermore, when applying the indicators to identify early-stage CRC a combination of CEA, TFRC and CA242 resulted in a ROC curve with an area under the curve of 0.861.
  
  
  CONCLUSIONS
  Five plasma protein biomarkers were found to be potential CRC discriminators and three of these were additionally found to be discriminators of early-stage CRC. These explorative data in symptomatic individuals demonstrates the feasibility of the multiplex proximity extension assay for screening of potential serological protein biomarkers and warrants independent analyses in a larger sample cohort, including asymptomatic individuals, to further validate the performances of our CRC biomarker panel.
authors.affiliation: Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Strandboulevarden 49, DK-2100, Copenhagen, Denmark. stenvang@sund.ku.dk.
authors.forename: Stine Buch
authors.initials: SB
authors.lastname: Thorsen
authors.forename: Martin
authors.initials: M
authors.lastname: Lundberg
authors.forename: Andrea
authors.initials: A
authors.lastname: Villablanca
authors.forename: Sarah Louise T
authors.initials: SL
authors.lastname: Christensen
authors.forename: Kirstine Christensen
authors.initials: KC
authors.lastname: Belling
authors.forename: Birgitte Sander
authors.initials: BS
authors.lastname: Nielsen
authors.forename: Mick
authors.initials: M
authors.lastname: Knowles
authors.forename: Nick
authors.initials: N
authors.lastname: Gee
authors.forename: Hans Jørgen
authors.initials: HJ
authors.lastname: Nielsen
authors.forename: Nils
authors.initials: N
authors.lastname: Brünner
authors.forename: Ib Jarle
authors.initials: IJ
authors.lastname: Christensen
authors.forename: Simon
authors.initials: S
authors.lastname: Fredriksson
authors.forename: Jan
authors.initials: J
authors.lastname: Stenvang
authors.forename: Erika
authors.initials: E
authors.lastname: Assarsson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001681:Biological Assay / Q000379:methods*; D014408:Biomarkers, Tumor / Q000097:blood*; D015179:Colorectal Neoplasms / Q000097:blood* / Q000175:diagnosis*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012372:ROC Curve; D012015:Reference Standards; D015203:Reproducibility of Results
chemical_list: D014408:Biomarkers, Tumor